Parameter estimation of induction machines under no-load test

This paper uses time-varied signals of voltage, current and rotor speed to compute the equivalent circuit parameters, moment of inertia, and friction coefficient of an induction machine. A time-varied impedance can be found by the time-varied voltage and current. From the variation of impedance to the rotor speed, the parameters of steady equivalent circuit can be found. According to the equivalent circuit and rotor speed, the torque can be found via established dynamic system model. On the basis of torque and rotor speed with time, moment of inertia and friction coefficient of the motor can be obtained. This paper uses the least mean square method to solve the above parameters. The initial values of least mean square are also described in this paper. This paper used estimated parameters to simulate the starting states of an induction machine to compare with the real one, accordingly, practicability and accuracy of this method has been proven.